The number of deaths in Fukushima caused by stress has almost topped the toll for fatalities caused by the 2011 earthquake and tsunami, according to a new survey.

As many as 1,539 residents in Fukushima prefecture, home to the damaged nuclear power plant, have reportedly suffered from stress since the disaster occurred two and a half years ago.

This figure is almost as high as the 1,599 Fukushima residents killed directly by the earthquake and tsunami which devastated the region, according to a survey carried out by the Mainichi Shimbun, the Japanese newspaper.

The bereaved relatives of a further 109 deceased residents have reportedly filed complaints, claiming they died as a result of stress, fatigue and aggravated health issues while living in evacuation shelters or temporary housing.

Fukushima, a region once famed for its green mountains and farm produce such as peaches and rice, was hit hard by the March 11 nuclear disaster as well as the tsunami and earthquake.

More than two years after the disaster, which caused significant damage to the Fukushima Daiichi nuclear power plant, around 160,000 residents remain in temporary housing, unable to return to their homes.

A string of legal cases are under way across the country, with thousands of Fukushima residents currently in the process of suing both the government and Tokyo Electric Power Co (Tepco), operators of the plant.

Last month, a group of around 140 residents launched legal action claiming 1 billion yen as compensation for the psychological stress caused by the nuclear accident after the authorities failed to take adequate safety measures to protect them.

Earlier this year, a further 1,650 residents and evacuees filed lawsuits in district courts with similar claims, reflecting the ongoing challenges facing those whose lives were transformed and homes were lost by the disaster.

Reports of the ongoing stresses faced by Fukushima residents coincides with continued troubles at the damaged plant, with a series of high-profile contaminated water leaks and radiation hot spots coming to light in recent weeks.

Shinzo Abe, the prime minister, intervened last week to declare the launch of an ambitious 47 billion yen (£304 million) scheme to stem leaks from the plant by constructing a frozen underground wall.

Late on Monday, TEPCO announced samples taken from a well at the site showed the presence of radioactive substances.

Reports said the utility believed it "now seems more likely" that leaks from tanks storing highly polluted water had made their way into subterranean water, which flows out to sea.